Defibrillator I  by Bob Keller
GemCad Ray Traces for RI = 1.76
Random Model Cosine Model ISO Model
Defibrillator I
Designed by Bob Keller December 2001 Bob Keller
A Simple Heart for Spinel, Garnet, Corundum
Angles for R.I. = 1.76 39 facets + 15 facets on girdle = 54
1-fold mirror-image symmetry 96 index
L/W = 1.007 T/W = 0.557 T/L = 0.553 P/W = 0.417 C/W = 0.158 H/W = (P+C)/W+0.02 = 0.595 P/H = 0.701 C/H = 0.265
Vol./W^3 = Vol./W^3 = 0.201 Brightness at 0° tilt for RI = 1.76 COS = 78.2 ISO = 90.4
Pavilion
cp 38.00 14-31-65-82 Cut to equal depth to make center point
1 39.00 06-90 Meet center point
2 40.59 10-86 Meet center point
3 41.21 14-82 Meet center point
4 41.40 19-77 Meet center point
5 40.46 23-73 Meet center point
6 39.20 31-65 Meet center point
7 39.84 40-56 Meet center point
8 42.91 48 Meet center point
g1 90.00 06-90 Match 1, set size
g2 90.00 10-86 Meet g1.1.2
g3 90.00 14-82 Meet g2.2.3
g4 90.00 19-77 Meet g3.3.4
g5 90.00 23-73 Meet g4.4.5
g6 90.00 31-65 Meet g5.5.6
g7 90.00 40-56 Meet g6.6.7
g8 90.00 48 Meet g7.7.8
Crown
a 33.08 06-90 Match g1, establish upper girdle line
b 34.65 10-86 Meet g1.g2.a
c 34.98 14-82 Meet g2.g3.b
d 36.40 19-77 Meet g3.g4.c
e 35.60 23-73 Meet g4.g5.d
f 35.97 31-65 Meet g5.g6.e
g 37.96 40-56 Meet g6.g7.f
h 40.00 48 Meet g7.g8.g
i 34.66 45-51 Meet h.g8.g7.g
j 31.40 27-69 Meet f.g6.g5.e
j 33.23 16-80 Meet d.g4.g3.c
j 32.31 08-88 Meet b.g2.g1.a
j 0.00 Table Meet l.a.a.1, l.b.c.k, others

The Defibrillator I Design File is available for GemCad users.

I designed Defibrillator I for a (relatively) easy to cut heart for a pyrope garnet of rich color that's been banging around in my rough box for a while now. This design is pretty bright as hearts go and is a good match for medium to deep saturated materials with RIs in the spinel-garnet-corundum range.

Begin the pavilion by carefully cutting four facets on indexes 14-31-65-82 at 38.00° to equal depth to establish a centered culet point. These four center point "finder" facets get cut away as pavilion facets 1-8 are subsequently cut to meet at this center point. The simple faceting in the "head" area on Defibrillator I should be facilitating if you are into vee notching your hearts.


Index of Gem Designs

Perfect Transfer Index

Table of Contents

Bob Keller